Underreamer.



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I APILIUL'HOI FILED IL! 10, 1918. 1,087,812.

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UNITED STATES PATENT OFFICE.

GUSTAVUS A. MONTGOMERY, OF OILFIELDS, CALIFORNIA.

UNDERREAMER.

7 '0 all whom it man concern:

Be it known that I, GUSTAVUS A. MONT- uoarnnr, a subject of Emperor of Russia, and a resident of Oilfields, in the county of Fresno and State of California, have invented anew and Improved Underreamer,

of which the following is a full, clear, and v body 10 has an axial bore 13, and a regisexact description.

My invention relates to an under reamer to be employed for enlarging a drill hole previously formed with an ordinary club bit in drilling for crude oil.

Objects of my invention are to provide an under reamer that may be readily repaired at small cost; to provide a large area of wearing surfaces between the cutters and their supporting elements; to provide a construction in which the wearing surfaces will be to a large extent protected against the entrance of abrasive matter; to provide perfeet seats for the cutters; to make provision for preventing the losing of the reamer cutters; to promote convenience in adjustlng the reamer in position to be lowered into the well; and to provide an under reamer, the body of which shall be free from subjoints.

It is also a design of my invention to improve in various particulars, devices of the general character indicated, to the end that strength may be promoted, as well as efliciency in operation, economy of manufacturle, and simplicity of adjustment and contro The distinguishing features of the invention, and the important structural elements characterizing the preferred embodiment which is illustrated as an example, will be more particularly explained in the specific description following.

Reference is to be had to the accompanying drawings forming a part of this specification, in which similar characters of reference indicate corresponding parts in all the views.

Figure 1 is a vertical section of an under reamcr embodying my invention. the reamer cutters being in the contracted positions to be lowered into' the well: Fig. 2 is a side elevation with parts in section, on the line 22 of Fig. 1; Fig. 3 is a vertical section on an enlarged scale of a portion of the reamcr, the cutters being in the expanded position; Figs. 4 and 5 are cross sections on an enlarged scale on approximately the lines 4-4 and 5-45 of Fig. .1; and Fig. 6 is an Specification of Letters Patent.

Application filed May 10. 1913.

Patented Feb. 17, 1914.

Serial No. 766,842.

enlarged side elevation of the removable core hereinafter particularly referred to.

In constructing a reamer in accordance with the illustrated example, a body 10 is provided, which terminates at its lower end in a shell 11 that receives the upper end of a removable core 12. The lower end of the tcring bore 14 is formed in the core 12, the lower end 14 of the bore 14 being of reduced diameter to present an internal shoulder.

Movable axially in the bores of the body and core is a spindle 15, which carries at its lower end expanding cutters 16. The connection between the cutters and spindle is effected by akey 17 which is received in a transverse slot 18 in the spindle, there being a slot 19 in the core registering with the slot 18, and of greater length than the latter, to permit vertical movement of the key in response to up and down movements of the spindle, as hereinafter referred to. The key at its ends is received also in transverse slots 20 formed in the shanks 16 of the cutters 16, whereby the cutters will be raised and lowered. The bits of the cutters. it will be 1 observed, are ofiset from the shanks.

The core 12 is formed at the ends of its slots 19 with recesses, the bottom surfaces 21 of which constitute seats for the shanks of the cutters. the said seats and the opposed surfaces of the shanks presenting mating inclines. 1" provide means to expand the cutters in their upward movement, while in the downward movement of the cutters they will be caused to contract and move inwardlv toward each other.

To force the spindle downward for moving the cutters. a wedge 22, indicated in dotted lines in Fig. 2, is employed, which is adapted to be passed through a transverse slot 23 transecting the bore 13, at the upper end of the latter, so that the wedge may engage the upper end of the spindle and force the same downwardly against the tension of a helical compression spring 24 which surrounds the spindle. The upper end of the spring seats against a shoulder provided on the spindle as by a washer 15" and nut or head 15", while the lower end of the spring seats on the shoulder provided by the reduced bore 14: of the core. The tendency of the spring therefore is to lift the spindle and thereby draw the cutters upwardly. The

head 15 has a groove 15 to receive the key 22. and when said groove is in line with slot 23, the slots 19, 20 will also aline with each other and will aline with slot 28 in the shell 11 when at the level of the latter.

I provide latching members so that the cutters will be held latched when in the lowcred position against the lifting action of the spring 24, for which plurpose use is made of mating shoulders on t e core and cutters respectively. Thus a shoulder or horizontal surface 12 is presented at the lower end of the inclined seat surfaces 21, and mating shoulders 16, best seen in Fig. 3, are formed on the opposed faces of the s anks 16 of the cutters. To guide the cutters and give them a lateral movement when raised and lowered by the spindle for expanding and contracting the reamer, co-actmg guide elements are provided on the-core and cutters. Thus, as seen best in Figs. 3 and 5, the cutters are formed with inclined grooves 25; and pins 26, preferably in the form of screw-studs, are provided on the core, which enter the said grooves.

By the described construction it will be seen that when the spindle is forced downwardly by a wedge 22, the spring 24 will-be placed under tension, and the spindle through the action of the key 17, will carry =thecutters downwardly,-the action of the pins 26 and grooves 25 giving a lateral movement to the cutters and causing the same to move downwardly and inwardly, followingthe inclined seat surfaces 21 until the shoulders 16 of'the cutters arrive below the shoulder 12 of the core 12, permitting the cutters toswing into latching engagement with the .core, as shown in 1. Upon the pressure on the spindle an pin being relieved by the withdrawal of the wedge22, the-spring will have a. tendency to draw the spindle'and cutters u wardly, but it will be resisted by the latche en agement of the described shoulders unti the reamer is lowered into the :well. When the utter bits emerge from the usual casing (not shown), they may expand as the point of engagement with key 17 results in suflicient leverage to disengage the shoulders and permit the expansion when the outward movement is not restrained by the casing.

The shell 11 de ending from the body 10 is integral with tie latter in the 0greferred construction, and therefore the b y of the rcamer is free from sub-'oints. For the insertion and removal of t e key 17, a slot 28 is formed in the shell 11, and the spindle may be so moved as to'temporarily bring the key-slots in the spindle, core and cutter shanks in line with said slot 28. The construction of the tool guards against the loss of the cutters by displacement of the key,

. since at no time will the key be'in re 'ster with the-slot -28 except for the bllGfOSt period in the up and down movements of the cutters; but if desired, the slot 28 may have a formation to receive a screw plug 29 to prevent any possibility of the key escaping aterally,

The lower end of the core at opposite sides of the cutters extends as at l2 below the lower edge of the shell 11 so as to afford an increased brace to the cutters. By reason of the inclined contact surfaces between the core and cutters, the latter will have a. perfect seat, wedging. themselves into position in response to the upward force of the spring, and therefore when in use, the cutters instead of becoming loose will tend to seat themselves more firmly. It will be obvious, furthermore. that the ('lescribed arrangement provides a very broad surface contact between the cutters and their seats. for distributing the wear. and moreover. the shell 11 provides a housing. the lower edge of which will be adjacent to the upper edges of the bits when the latter are in the working position, the arrangement minimizing the tendency of sand or grit to enter l'ictwecn the wearing surfaces of the cutter shanks and their seats. Provision. howevermay be made for the escape of any grit from the shell, such for instance as the formation of clearance holes 30 in the shell 11. A hole 30 diametrically opposite slot 528 permits entrance of a tool to drive out the key 17.

The connection between the core and shell may be effected in any approved manner. advantageously by forming a thread of coarse pitch, as at 12, on the upper end of the core to engage corresponding threads in the interior of the shell, and a pin 31 may be provided additionally, to pass through the shell and core.

The removable core permits of repairs being made with convenience and despatch and at small cost. Should the efficiency of the tool be impaired by wear between the, cutters and core. the core may be removed and planed down, and shortened if necessary, without the necessity of discarding it,

thus prolonging the life. of the core at small cost. Even the total replacing of the core will cost but little. Moreover. should the shell of the body be impaired by use it may be cut off at its lower end to correspond with any shortening of the cutter shanks and core. the original manufactured length making provision for this change.

Having in mind the possible breaking of the cutters which would occur. if at all. at

the juncture of the bits and shanks, l pro-.

vide bolts or pins 27 ranging lengthwise in the cutters from the shoulders 16" downwardly to the inner faces of the hits, the latter having recesses 16 to receive the bolt heads. The pins it will be. seen range in tho cutters across the juncture of the shanks and bits so that if a break occurs at this point, the broken parts will be held together and will be drawn upwardly with the reamer.

It is to be understood that the under reamer operates in the same manner as others, the cutter bits being positioned below the drive pipe shoe (not shown).

Having thus described my invention, I claim as new, and desire to secure by Letters Patent:

1. An under reamer, comprising a body, reamer cutters, a member at the lower end of the body providing seats for the cutters, and relatively to which the cutters may be raised and lowered, said member having a portion between the cutters with which the latter have latching engagement when lowered, spring-pressed means tending to raise said cutters, and means for guiding the cutters into the mentioned latchmg engagement when moved in opposition to the spring pressure.

2. An under reamer, com rising a body a de ending member at the ower end of the bo y presenting oppositely inclined seats,

reamer cutters resenting inclines corresponding with sald seats, means for raising and lowering the cutters, and oo-acting means on the said depending member an on the reamer cutters adapted for latching engagement when the cutters are moved to the lowered position.

8. An under reamer comprising a body, a removable depending core at the lower end of the body, reamer cutters seating on said core, the lower end of the core presenting a shoulder and the cutters havin opposite shoulders to engage said shoul er of the core, a spindle carr ing said cutters and movable ongitudina ly in the body and core, a coiled spring on said spindle tending to lift the same, and means for iding the cutters into engagement with tie shoulder of the core when they are carried downward by the spindle moving in opposition to the spring.

4. An under reamer comprising a body havin a depending shell terminating in an open ower end, a depending core within the shell there being spaces between the shell and core, expanding reamer cutters having bits below the lower edge of the shell and having shanks fittin in the spaces between the shell and core, t e cutters being movable to raise or lower the same, means for raising and lowering the cutters relatively to the core, and means to respectively expand and contract the cutters as they are raised and lowered, the reamers in the lowered position having latching engagement with the core.

5. An under reamer, comprising a body terminating in a depending shell open at its lower end, a removable core held within said shell, expanding cutters fitting between the shell and core, an axially movable spindle in the body and core and a transverse key carried by the spindle, said spindle being slotted to removably receive said key, the core having a transverse slot of greater length than the slot of the spindle, reamer cutters having slots registering with those of the spindle and core, there being a slot in the shell, at one side, with which the slots in the spindle and cutters may be brought into register for the entrance and removal of the key, the said shell presentin a closed wall to the ends of the key in bot the lowered and raised positions of the key.

6. The herein described cutter for reamers having a bit and a shank, and a separate elongated element ranging len thwise in the gutter across the junction of t e shank and 7. An under reamer, comprisin a body terminating at its lower end in a epending shell a core removably held to the body within the shell, the body having a bore and the core havin r a registering bore, a spindle in the sai bores, a helical spring surrounding the spindle and tending to lift the same, there being a transverse slot in the body at the upper end thereof to receive a wedge to lower the spindle against the tension of the spring, said spindle having a transverse key-slot at its lower end and the core having a registering transverse slot of greater length than that of the spindle and having side recesses communicating with the slots and formin seats, reamer cutters having slotted shan (s receivable in the recesses of the core, between the latter and the shell, the said cutters and the seat surfaces of the core having mating inclines, a transverse key removably fitting the slots of the spindle core and cutter shanks, there being a slot in the shell for the entrance and removal of the key, and the core and shanks of the cutters having guide pins and inclined guide grooves, the cutters furthermore having latching members engageable with the core and carried downward by a lowering of the spindle.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

GUSTAVUS A. MONTGOMERY.

Witnesses:

B. C. WILLIAMS, H. R. Cnozmn.

Copies of this patent may be obtained tor five cents each, by addressing the "Commissioner of Patents, Washington, D. 0." 

